The invention relates to battery powered radio transmitters, in particular, garage door opening devices but includes electronic gates, door locks, lights and the like.
Battery powered radio transmitters are normally kept on the dashboard, sun visors or in the shift console of a vehicle, thus exposing them to hazards such as theft, unwanted activation if the unit falls from its resting place or a youngster could activate the device when it is not suitable to so do and finally, the sun's rays could damage the transmitter over a period of time. In addition, the unit is one which requires batteries that have to be replaced periodically.
Prior art devices of this type are seen, for example, in Marcus, U.S. Pat. No. 4,241,870 and U.S. Pat. No. 4,247,850, as well as Bush, U.S. Pat. No. 3,936,833. The Marcus devices, for example, disclose transmitters which are positioned in a passenger compartment of a vehicle and there is a special power supply from the automobile electrical system for the transmitter which, when removed, relies on battery power. In the '850 patent, the transmitter is designed to be incorporated into a sun visor and powered from the main electrical source in the automobile.